A conventional receiver for a continuous phase frequency shift keying signal repeatedly, successively adds 0, +π/2, +2π/2, and +3π/2 to phase information of a Gaussian minimum shift keying (GMSK) signal so as to facilitate processing at a subsequent stage with the GMSK signal regarded as a binary phase shift keying (BPSK) signal.
However, the conventional receiver detects the phase information of the signal by mutually using an in-phase signal and a quadrature signal so that there is a problem that power consumption is large.